When Zappos.com founder Nick Swinmurn had the initial idea to launch an online shoe retailer in the '90s, he sought out the leanest way possible to test whether customers were willing to buy shoes online. Instead of spending time building an infrastructure and inventory systems, Swinmurn went to local shoe stores, took pictures of products and posted them online.

If a customer purchased the product, Swinmurn bought the shoes from the brick-and-mortar store at full price to ship to his customer. When the concept actually worked, he knew it was go-time.

Almost 20 years later, in today’s retail environment, adopting this type of low-risk, lean-startup mentality, with a “fail fast, fail cheap” approach, is the number one strategy for success. Here are five lessons to help you nail product innovation through an agile approach.

Take lean to the extreme.

Forget about scaling at the beginning. Instead, identify and embrace the bare minimum you need to develop an end-to-end solution, even if it’s manual. Then build out a basic product infrastructure to mimic a more scalable process and iterate as you progress through development and validation.

This is called the “garage phase” of innovation. Thought leader and author Marty Cagan explained a similar “light-weight” process to product development in his book, Inspired: How to Create Tech Products Customers Love. By embracing a lean approach, Cagan wrote, you’re making room for the next great idea and continuing to discover and improve with each step you take along the way.

Don’t overcomplicate.

Consider simple solutions that are as innovative and personalized as they are valuable for your customer and business objectives. Recently, our company, CarMax, launched 360-degree-camera technology to allow shoppers to interact with 360 photos on carmax.com and experience the inside of a prospective car as if they were sitting in it.

The goal was a more optimized and personal online customer experience, and it started with a selfie stick. This basic low-cost solution required little time, training and resources, and was quickly scalable.

Starbucks is another example: The company excels in creating a simple customer experience because of its focus on seamless personalization: Baristas serve coffee ID'd by the customer’s name, and each location has the same look and feel but is personalized to the geographic location.

Recognize that innovation doesn’t happen in a lab.

Don’t isolate your R&D in a lab; instead, send your team out to the field while developing your solution, in order to deliver real-time adjustments and build your awareness of variables you may not have considered before. Test different approaches, speak with customers and stakeholders and understand all the possible challenges or failures that could happen.

When Nordstrom was attempting to develop a digital way to help sunglass shoppers make a purchase decision, members of the innovation team embedded themselves at a Nordstrom store for a week, talking to real customers, showing prototypes and adjusting those product samples based off those customers' feedback.

Innovate for both internal and external audiences.

Remember the two “customers” you’re innovating for -- both the end user and the associates who will be using the product. By finding a simple solution that works for everyone and training for the rollout, you'll be setting yourself up for success. Qualitative testing and immediate feedback can also help your team better understand usability and the overall customer experience the product is delivering. A product just might fail if there’s a lack of understanding about its functionality.

Avoid product remorse.

By starting with a minimum viable product, you'll be able to get something in front of customers as early as possible before you've invested too much time and energy into it. Take a page from Jeff Gothelf's book,Lean UX, and don’t sit on value or wait to arrive at a perfect solution before

implementing at the level of "good" can be good enough and be your starting point for further iteration. You’re not going to learn everything and anticipate every problem before you introduce a product. And, if you wait too long, the market may shift.

Before co-founding Groupon, Andrew Mason spent almost two years working on a product called The Point, an online platform for social activism. While The Point never gained steam, Mason did observe his customer base using a featured offering for a group discount on products. Because of good timing and openness to learning, he was able to pivot and create Groupon.

By learning quickly and failing fast, yourself, you'll be better able to keep in lock step with customer expectations, to leave behind the ideas that aren’t helping your customers and to deliver the experience your customers want today.